Topic outline

    • The Living Organisms and Their surroundings

      Q49. How are plants in the desert adapted?

      Ans. The leaves in desert plants are either absent, very small, or they are present in the shape of spines. This helps in reducing loss of water from the leaves through transpiration. The leaf-like structure in a cactus is, in fact, its stem. Photosynthesis in these plants is usually carried out by the stems. The stem is also covered with a thick waxy layer, which helps to retain water. Most desert plants have roots that go very deep into the soil for absorbing water.


      Q50. How do deer adapt themselves to live in forest or grassland?

      Ans. A deer is an animal that lives in forests and grasslands. It has strong teeth for chewing hard plant stems of the forest. It has long ears to hear movements of predators. The eyes on the side of its head allow it to look in all directions for danger. The speed of the deer helps them to run away from the predators.

      Q51. How animals in mountain regions are adapted to the condition there?

      Ans. Animals living in the mountain regions are adapted to the conditions there. They have thick skin or fur to protect them from cold. For example, yaks have long hair to keep them warm. Snow leopard has thick fur on its body including feet and toes. This protects its feet from the cold when it walks on the snow. The mountain goat has strong hooves for running up the rocky slopes of the mountains.


      Q52. How do the features of lion help it to survive in grassland or forest?

      Ans. A lion lives in a forest or grassland and is a strong animal that can hunt and kill animals like deer. It is light brown in color. Its light brown color helps it to hide in dry grasslands when it hunts for prey (animals to eat). The eyes in front of the face allow it to have a correct idea about the location of its prey.


      Q53. Do plants also excrete?

      Ans. Yes, they do. However, the mechanisms in plants are a little different. Some harmful or poisonous materials do get produced in plants as wastes. Some plants find it possible to store the waste products within their parts in a way that they do not harm the plant as a whole. Some plants remove waste products as secretions.


      Q54. Do plants also move?

      Ans. Plants are generally anchored in soil so they do not move from one place to another. However, various substances like water, minerals and the food synthesized by them moves from one part of the plant to other. They show movements of their parts such as opening and closing of stomata, and flowers, growth of roots toward the soil and shoot toward the light.

      Q55. How do dolphins and whales breathe?

      Ans. There are some sea animals like dolphins and whales that do not have gills. They breathe in air through nostrils or blowholes that are located on the upper parts of their heads. This allows them to breathe in air when they swim near the surface of water. They can stay inside the water for a long time without breathing. They come out to the surface from time to time, to breathe in air.


      Q56.What kinds of leaves are found in submerged plants? How do these leaves protect themselves from getting damaged underwater?

      Ans. Some aquatic plants are totally submerged in water. All parts of such plants grow under water. Some of these plants have narrow and thin ribbon-like leaves. These can bend in the flowing water. In some submerged plants, leaves are often highly divided, through which the water can easily flow without damaging them.


      Q57. How sea animals like squids and octopus are adapted to live in water?

      Ans. There are some sea animals like squids and octopus, which do not have this streamlined shape. They stay deeper in the ocean, near the seabed and catch any prey that moves towards them. However, when they move in water they make their body shapes streamlined. These animals have gills to help them use oxygen dissolved in water.